The A4 was closed for a time on Saturday between Ballabooie Road and the Switchback following the collision involving a car and a motorcycle at around 3.10pm.
Isle of Man Constabulary is now appealing for anyone with information or who witnessed the collision to come forward.
‘We are appealing to anyone who may have witnessed the collision to please contact Police Headquarters on 01624 631212 and quoting the reference 97/3001/25 to assist us with our enquiries.
‘Alternatively, if you have information and wish to share it anonymously, you can do so by calling Crimestoppers on 0800 555 111.’
The Great North Air Ambulance Service's (GNAAS) was also called to the scene and confirmed one casualty was airlifted to hospital.
A spokesman said: ‘On Saturday our critical care team was activated at 3.40pm to reports of a road traffic collision in the Peel area of the Isle of Man
‘We had a doctor and two paramedics on board our aircraft and they arrived on scene at 4.14pm.
‘Our team worked alongside the Isle of Man Ambulance Service to assess and treat a patient before airlifting them to hospital.’
The condition of the patient is not known, and it is not clear if there were any other casualties following the collision.